engleski

Water Vapour Transmission of Thermal Protective Woven Fabrics

Water vapour permeability is a property of paramount importance for the production of woven fabrics for firefighting clothing. The porosity and the permeability of water vapour are influenced by fabric constructional and structural parameters, such as weave, warp and weft density, fabric thickness, yarn fineness, etc. Fabrics with a high degree of protection against high temperatures must have satisfactory comfort properties, in particular good breathability to ensure the transfer of metabolic heat and steam from sweating to the environment. By testing the resistance of the passage of water vapour through the materials, their breathability or wearing comfort can be defined. In this paper, the comfort of woven fabrics for protection against high temperatures depending on water vapour permeability and porosity of the structure was investigated. The influence of structural and construction parameters and material composition on the above properties was also investigated. Eight woven fabric samples were woven on a laboratory weaving machine. Samples were made in two different weaves (K2/2 and ripstop) and four different weft fineness and compositions from different proportions of polyamide, meta-aramid and viscose/cotton fibre. All samples were woven with the same aramid warp, fineness 14x2 tex in the same density and under the same weaving conditions. In addition to the basic characteristics of the samples, the water vapour transmission through the sample according to the ASTM E96 method was performed. The results showed that the material composition, structural and constructional characteristics of woven fabrics affect its water vapour transmission and thus the wearing comfort. In general, the more porous fabric structure, as in a case of samples in ripstop weave, has a higher rate of water vapour transmission compared to twill weave fabrics. Furthermore, the weft yarn fineness has a direct impact on the fabric porosity and thus on the rate of water vapour transmission which is higher in fabrics with a finer weft yarn. By determination of the samples warp and weft density, differences in values were found, and accordingly the fabric porosity was different from expected. This is especially noticeable with samples in the ripstop weave.

Water Vapour Permeability, Protective Woven Fabrics, Thermal Protection, Structure Porosity, Fabric Comfort

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